Charged particle beam device, multi-beam blanker for a charged particle beam device, and method for operating a charged particle beam device

ABSTRACT

A multi-beam charged particle beam device is described. The multi-beam charged particle beam device includes a charged particle source configured to emit a primary charged particle beam; an aperture arrangement having openings configured to generate at least a first beamlet and a second beamlet of the primary charged particle beam; and a blanking device, the blanking device includes at least a first blanking deflector for the first beamlet and a second blanking deflector for the second beamlet; and a shield assembly having a first shielding element partially or fully surrounding the first blanking deflector.

FIELD

Embodiments of the present disclosure relate to a charged particle beamdevice, a multi-beam blanker for a charged particle beam device,particularly a multi-beam blanker per beamlet of a multi-beam singlecolumn charged particle beam device, and a method for operating acharged particle beam device. Embodiments of the present disclosureparticularly relate to electron beam inspection (EBI).

BACKGROUND

Charged particle beam devices have many functions in a plurality ofindustrial fields, including, but not limited to, electron beaminspection (EBI), critical dimension (CD) measurements of semiconductordevices during manufacturing, defect review (DR) of semiconductordevices during manufacturing, exposure systems for lithography,detecting devices and testing systems. Thus, there is a high demand forstructuring, testing and inspecting specimens within the micrometer andnanometer scale. Micrometer and nanometer scale process control,inspection or structuring can be done with charged particle beams, e.g.electron beams, which are generated and focused in charged particle beamdevices, such as electron microscopes. Charged particle beams offersuperior spatial resolution compared to, for example, photon beams dueto the short wavelengths.

High throughput electron beam inspection (EBI) systems can utilizemulti-beam charged particle beam devices, such as electron microscopes,that are able to create, focus and scan multiple primary chargedparticle beams inside a single column of the charged particle beamdevice. A sample can be scanned by an array of focused primary chargedparticle beams or beamlets, which in turn create multiple signal chargedparticle beams. The individual signal charged particle beams can bemapped onto detection elements.

The throughput of single beam electron inspection at high resolution isreaching a limit. A solution can be provided by multiple electron beams.Generally, there are different approaches, namely providing multiplesingle-beam columns, a single column having multiple charged particlebeamlets, or multiple columns with multiple charged particle beamlets.

Charged particle inspection systems tend to charge non-conductive areason the sample or specimen. Charging of non-conductive areas may causeimage degradation of the imaging characteristics for the surroundingconductive areas. Furthermore, sensitive areas may be damaged byelectron beam irradiation.

In view of the above, improved charged particle beam devices andimproved methods for operating a charged particle beam device thatovercome at least some of the problems in the art are beneficial.

SUMMARY

In light of the above, a charged particle beam device, a blanker formultiple beams for a charged particle beam device, and a method foroperating a charged particle beam device are provided. Further aspects,benefits, and features of the present disclosure are apparent from theclaims, the description, and the accompanying drawings.

According to an aspect of the present disclosure, a multi-beam chargedparticle beam device is provided. The multi-beam charged particle beamdevice includes a charged particle source configured to emit a primarycharged particle beam; an aperture arrangement having openingsconfigured to generate at least a first beamlet and a second beamlet ofthe primary charged particle beam; and a blanking device, the blankingdevice includes at least a first blanking deflector for the firstbeamlet and a second blanking deflector for the second beamlet; and ashield assembly having a first shielding element partially or fullysurrounding the first blanking deflector.

According to an aspect of the present disclosure, a method for operatinga charged particle beam device is provided. The method includesgenerating a primary charged particle beam; generating a first beamletfrom the primary charged particle beam and a second beamlet from theprimary charged particle beam; scanning the first beamlet and the secondbeamlet over a specimen; blanking the first beamlet with a firstdeflection field of a first blanking deflector for the first beamlet;and shielding the first deflection field of the first blanking deflectorto reduce crosstalk to the second beamlet.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments. The accompanying drawings relate to embodiments of thedisclosure and are described in the following:

FIG. 1A shows a schematic view of a charged particle beam deviceaccording to embodiments described herein;

FIG. 1B shows a schematic view of a further charged particle beam deviceaccording to embodiments described herein;

FIG. 2 shows a schematic view of a blanking device having a shieldassembly according to embodiments described herein, wherein a beamsplitter and a blanking device are provided;

FIG. 3A shows a schematic view of a blanking device having a shieldassembly according to embodiments described herein, wherein a furtherarrangement of a beam splitter and a blanking device is provided;

FIG. 3B shows a schematic view of a blanking device having a shieldassembly according to embodiments described herein, wherein a furtherarrangement of a beam splitter and a blanking device is provided;

FIG. 3C shows a schematic view of a blanking device having a shieldassembly according to embodiments described herein, wherein a yetfurther arrangement of a blanking device is provided;

FIG. 4 shows a schematic view of a blanking deflector according toembodiments described herein;

FIGS. 5A and 5B show schematic views of an electrostatic multipoledevice such as a blanking deflector according to embodiments describedherein;

FIG. 6 shows a flowchart of a method for operating a charged particlebeam device according to embodiments described herein; and

FIGS. 7A and 7B show schematic views of a beam dump according toembodiments of the present disclosure that may be used with a multi-beamcharged particle beam device according to embodiments of the presentdisclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Reference will now be made in detail to the various embodiments of thedisclosure, one or more examples of which are illustrated in thefigures. Within the following description of the drawings, the samereference numbers refer to same components. Only the differences withrespect to individual embodiments are described. Each example isprovided by way of explanation of the disclosure and is not meant as alimitation of the disclosure. Further, features illustrated or describedas part of one embodiment can be used on or in conjunction with otherembodiments to yield yet a further embodiment. It is intended that thedescription includes such modifications and variations.

Without limiting the scope of protection of the present application, inthe following the charged particle beam device or components thereofwill exemplarily be referred to as a charged particle beam device usingelectrons as charged particles. However, other types of primary chargedparticles, e.g. ions, could be used. Upon irradiation of a specimen orsample by a charged particle beam (also referred to as “primary chargedparticle beam”), signal charged particles, such as secondary electrons(SE), are created, which may carry information about the topography,chemical constituents and/or electrostatic potential of the sample andothers. The signal electrons can include at least one of secondaryelectrons, backscattered electrons and Auger electrons. The signalcharged particles can be collected and guided to a sensor, e.g., ascintillator, a pin diode or the like.

According to embodiments described herein, charging of non-conductiveareas on the sample or specimen can be provided for an electron beamimaging apparatus, e.g. an electron beam inspection apparatus. Amulti-beam blanker is provided, wherein primary charged particle beamsor beamlets can be blanked individually. The beam blanking device mayblank and unblank the electron beam(s). Each beamlet may be individuallycontrollable, to maximize the throughput. As compared to beam blankersfor e.g. lithography, the device should be fast, i.e. blank the beams inthe microsecond range, i.e. less than the time scale to scan a singleline. Further, blanking one beamlet should not affect the imagesobtained with the other beamlets, i.e. there should be no crosstalkbetween beam blanking elements.

According to embodiments of the present disclosure, a charged particlebeam column having a source, i.e. a single source, is provided. Aplurality of charged particle beamlets, i.e. primary charged particlebeamlets, is generated within the charged particle beam column, forexample, a single column having multiple beamlets. The plurality ofcharged particle beamlets is scanned over a specimen. Particularly uponscanning of an area at the border between an insulator and an area to beinspected, one of the plurality of beamlets may be scanned over theinsulator while another of the plurality of beamlets is scanned over thearea to be inspected. Scanning over an insulator, for example, a stronginsulator, charging of the specimen may occur. The charging of thespecimen may result in charging artifacts in the image to be provided.Accordingly, one or more of the beamlets scanning over the insulator canbe blanked. Scanning of the other beams can be provided.

According to an embodiment, a multi-beam charged particle beam device isprovided. The device includes a charged particle source configured toemit a primary charged particle beam; an aperture arrangement havingopenings configured to generate at least a first beamlet and a secondbeamlet of the primary charged particle beam; and a blanking device, theblanking device comprises; at least a first blanking deflector for thefirst beamlet and a second blanking deflector for the second beamlet;and a shield assembly having a first shielding element at leastpartially surrounding the first blanking deflector. The shield assemblyis configured to reduce cross-talk from a first blanking deflector for afirst beamlet to the second beamlet, i.e. a beamlet different from thefirst beamlet.

FIG. 1A shows a schematic view of a charged particle beam device 100according to embodiments described herein. The charged particle beamdevice 100 can be an electron microscope, such as a scanning electronmicroscope (SEM). The charged particle beam device 100 includes a columnhaving a column housing 101.

The charged particle beam device 100 includes a charged particle source20 configured to emit a (primary) charged particle beam 14, a condenserlens arrangement 110, an aperture arrangement 120 configured to generatetwo or more beamlets 14A, 14B, 14C of the primary charged particle beam14, and a multipole arrangement 130 configured to act on the two or morebeamlets 14A, 14B, 14C, particularly to act on the first beamlet and thesecond beamlet separately. The aperture arrangement 120 includes aplurality of openings 122. A multipole arrangement 130 can be configuredto act on the two or more beamlets. The condenser lens arrangement 110can include a magnetic condenser lens or an electrostatic condenserlens, or a combined magnetic electrostatic magnet condenser lens. Themagnification and/or the current of the beamlets can be controlled bythe condenser lens arrangement.

According to some embodiments, which can be combined with otherembodiments described herein, the condenser lens arrangement includesone or more condenser lenses, such as a single condenser lens or two ormore condenser lenses. A condenser lens arrangement can be configured toprovide a beam path with cross-over and/or a beam path withoutcross-over. The condenser lens arrangement 110 can have an adjustablelens excitation for at least one of changing a focal length and changingan illumination angle of the aperture arrangement 120. For example, thecondenser lens arrangement can be provided with a controllable lensexcitation for a focal length change enabling a variable sourcemagnification and/or demagnification. Additionally or alternatively, thecondenser lens arrangement can be provided with the controllable lensexcitation for controlling the illumination angle of the aperturearrangement and/or the multipole arrangement (e.g., a deflector array).In some implementations, the condenser lens arrangement 110 can providean essentially parallel illumination of the aperture arrangement 120.

The aperture array 120 separates the primary beam emitted by the chargedparticle source in primary beamlets. The aperture array can beconsidered as a portion of a beam splitter and may, for example, be atground potential. The beam splitter separates the “main” beam intomultiple beamlets. The multipole arrangement 130 can direct the beamletsto the coma free plane of the objective lens. The opening in theaperture arrangement 120 and, thus, the beamlets may be arranged in anarray form or a ring form.

According to some embodiments, which can be combined with otherembodiments described herein, one single charged particle source can beprovided. The charged particle source 20 can be a high brightness gun.For example, the charged particle source 20 can be selected from thegroup including a cold field emitter (CFE), a Schottky emitter, a TFE,or another high brightness e-beam source. The source can be at apotential of −30 kV and the emitted electrons are accelerated to anenergy of 30 keV by an extractor electrode and anode held at ground. Thesource can be configured to provide a uniform illumination to an angleof −40 mrad, e.g. at 30 kV extraction voltage.

The condenser lens arrangement 110 illuminates the aperture arrangement120 with the (primary) charged particle beam 14, such as an electronbeam. The resulting two or more beamlets 14A, 14B, and 14C can bedeflected using deflectors 6A, 6B and 6C of the multipole arrangement130 such that the two or more beamlets 14A, 14B, and 14C appear to comefrom different sources. For example, the electrons of the beamletsappear to be emitted from different locations in a plane 21 of thecharged particle source 20 perpendicular to an optical axis 4. As shownin FIG. 1A, the electrons provided by the source appear to come fromvirtual sources.

According to some embodiments, which can be combined with otherembodiments described herein, a beam separator 114, i.e., a separatorseparating the primary beamlets from the signal beamlets, can beprovided by magnetic deflectors or a combination of magnetic andelectrostatic deflectors, e.g. a Wien filter. A scanning deflector 12may scan the beam or beamlets over the surface of the sample 8. Theprimary beamlets, i.e. the two or more beamlets, are focused on thespecimen or sample 8 using a common objective lens. The primary beamletscan pass through one opening in the objective lens 10. The sample 8 isprovided on a sample stage 7, which can be configured to move the sample8 in at least one direction perpendicular to the optical axis 4. Due tothe combined effects of the deflectors 6A-6C, e.g., electrostaticmultipole devices, and the objective lens 10, multiple spots (images ofthe beam source 2), each corresponding to one of the beamlets arecreated on the specimen or sample 8.

A “sample” or “specimen” as referred to herein, includes, but is notlimited to, semiconductor wafers, semiconductor workpieces, and otherworkpieces such as memory disks and the like. Embodiments of thedisclosure may be applied to any workpiece on which material isdeposited or any workpiece which is structured. Upon irradiation of thesample 8 by the electron beam, signal charged particles, such assecondary electrons (SE), are created, which may carry information aboutthe topography, chemical constituents and/or electrostatic potential ofthe sample and others. The signal charged particles can be collected andguided to a detector device, which can be a sensor, e.g., ascintillator, a pin diode or the like.

According to some embodiments, which can be combined with otherembodiments described herein, the objective lens 10 can be anelectrostatic magnetic compound lens, particularly having anelectrostatic lens that reduces the energy within the column from a highenergy within the column to a lower landing energy. The energy reductionfrom the column energy to the landing energy can be at least a factor of10, for example at least a factor of 30.

In some implementations, a retarding field including a potentialprovided to the sample 8 can be provided. According to yet furtherimplementations, which can be combined with other embodiments describedherein, a configuration, in which the column is at ground potential andthe charged particle source 20 and the sample 8 are at a high potentialcan be provided. For example, most or all of the column components canbe provided at ground potential.

As for instance shown in FIG. 1A, a plurality of or all primary beamletscan be scanned across the surface of the sample 8 using a commonscanning deflector. According to some embodiments, which can be combinedwith other embodiments described herein, the scanning deflector 12 canbe within the objective lens 10 or close to the objective lens 10.According to some embodiments, which can be combined with otherembodiments described herein, the scanning deflector 12 can be anelectrostatic and/or magnetic octupole.

The charged particle beam device 100 shown in FIG. 1A includes a signalelectron optics. Particles released from or backscattered from thesample 8 form signal beamlets carrying information about the sample 8.The information can include information about the topography of thesample 8, the chemical constituents, the electrostatic potential, andothers. The signal beamlets are separated from the primary beamletsusing the beam separator 114. A beam bender (not shown) may optionallybe provided. The beam separator can, for example, include at least onemagnetic deflector, a Wien filter, or any other devices, wherein theelectrons are directed away from the primary beam, e.g. due to thevelocity depending Lorenz force.

FIG. 1B shows another beam path of the column including a beamseparation between primary beamlets and signal beamlets. The beamseparator 114 can be provided as a magnetic deflector. A furthermagnetic deflector 115 is provided. The two magnetic deflectors deflectthe beamlets in opposite directions. The beamlets may be tilted by thefirst magnetic deflector 115 and aligned with an optical axis 4 of anobjective lens (e.g. vertical in FIGS. 1A and 1B) by the second magneticdeflector. Signal beamlets return through the objective lens up to thebeam separator 114 which separates signal beamlets from the primarybeamlets.

The signal beamlets can be focused by a focusing lens 172. The focusinglens 172 focuses signal beamlets on detector elements of a detectorassembly 170, such as sensors, scintillators, pin diodes or the like.For example, a detector assembly may include a first sensor to detect afirst signal beamlet generated by a first beamlet and a second sensor todetect a second signal beamlet generated by a second beamlet. Accordingto other embodiments, focusing of the secondary beamlets can beperformed by a lens system which enables calibration of magnificationand rotation. According to some embodiments, one or more deflectors 174,176 are provided along the path of the signal beamlets.

According to embodiments described herein, a multi-beamlet column isprovided with a number of beams, such as two or more, or 5 or more, or 8or more, according to some examples, up to 200. The multi-beamlet columnis configured such that the multi-beamlet column can also be arrayed ina multi-column system.

According to embodiments described herein, the pitch on the specimen,e.g. a wafer, i.e. a minimal distance between two primary beamlets onthe specimen, can be 10 μm or above, for example 40 μm to 100 μm.Accordingly, embodiments provide a multi-beam device which generates areasonable number of primary electron beamlets within one electronoptical column, wherein crosstalk between the beamlets upon travellingthrough the column is reduced.

According to embodiments of the present disclosure, a multi-beam blankeris provided. FIG. 1A show a blanking device 150. The blanking device 150can blank individual beamlets. For example, FIG. 1A shows the beamlets14A, 14B, and 14C, wherein the beamlet 14B is blanked, and the otherbeamlets are unblanked. FIG. 1A shows the blanking device 150downstream, for example, immediately after, the aperture arrangement120. The blanking device 150 includes a plurality of blankers. FIG. 1Aexemplarily shows blankers 15A, 15B, and 15C. For example, the blankerscan be arranged on an array or a ring. The array form or ring formcorresponds to the array form or ring form (or another form) of theopenings 122 in the aperture arrangement 120. The blankers can turn eachbeamlet off and on. If a beam is blanked, it may be deflected radiallyoutwards towards the beam stop 160. The beam stop may have one or morebeam dumps.

According to embodiments of the present disclosure, the blanking deviceincludes a shield assembly 155. The shield assembly reduces or avoidscross-talk. A blanker of one beam has reduced or substantially no (<10⁴orders of magnitude reduced) influence on another beamlet or thedeflection of another beamlet, e.g. a neighboring beamlet. According toembodiments described herein, the blankers of the blanking device arefast and for being utilized in an imaging system, such as an EBI system,influence of fields generated by a blanker are strongly suppressed.Accordingly, blanking devices of, for example, lithography systems nothaving the significantly reduced cross-talk of the blankers may not besuitable for EBI.

According to some embodiments, which can be combined with otherembodiments described herein, a blanking device for an EBI multi-beamsystem, particularly with individual beamlet blanking provides a fastblanking of a beamlet. For example, a beamlet can be blanked within 10μs or below. For example, a blanking deflector, for example a firstblanking deflector for a first beamlet and a second blanking deflectorfor a second beamlet can be controlled with signals provided by aplurality of lines to deflector elements, e.g. electrodes. The linesprovide electrical signals to the deflector elements. According to someembodiments, which can be combined with other embodiments describedherein, the lines can be high conductive and low capacitance lines. Forexample, the capacitance of the combination of lines and deflectorelement, i.e. deflector electrode, can be 100 pF or below. A resistanceof the lines (or conductors) can be 200 Ohm or below. According to yetfurther embodiments, transient signals may be delimited to be within theμs region. According to some embodiments, which can be combined withother embodiments described herein, the first blanking deflector for thefirst beamlet and/or a second blanking deflector for the second beamletare controlled by lines or conductors having a low resistance and lowcapacitance.

Embodiments of the present disclosure provide a multi-beam inspectioncolumn, wherein beamlets can be individually turned off and on. Asexemplarily shown in FIG. 2, micro blankers of a blanking device 150 canbe provided. Each micro blanker is configured to create an electrostaticdipole field per beamlet. When activated, the electrostatic dipolefields blank the beamlet, i.e. steer the beamlet away from the primarypath into a beam-dump or aperture such that the blanked beamlet nolonger reaches the wafer. Including a shield assembly according toembodiments of the present disclosure allows for a blanking operationnot affecting the image produced by the non-blanked beamlets. Thenon-blanked beamlets remain on their original path.

According to embodiments of the present disclosure, and as exemplarilyshown in FIG. 1A, the blanking device 150 can be located close (within 5times to 15 times the length of the beam splitter (e.g. 10 times, suchas 0.5*10=5 mm). A small distance between the beam splitter and theblanking device reduces alignment difficulties and may eliminatealignment deflectors between the two elements.

According to yet further embodiments, the blanking device can beprovided at the same position along the optical axis as the beamsplitter. For example, a multi-pole element can be provided, and havingmultiple electrodes are provided around a beamlets position. Some of theelectrodes may serve for beam blanking and some of the electrodes mayserve for beam splitting, i.e. generation of multiple charged particlespots on the specimen or generation of two or more virtual chargedparticle sources, respectively. According to yet further embodiments,which can be combined with other embodiments described herein, ablanking deflector, e.g. a first blanking deflector, includes amultipole device for splitting the first beamlet from the second beamletand for blanking the first beamlet. According to yet further additionalor alternative modifications, the multipole device can be controlled toadditionally generate aberration correction fields, e.g. for correctionof hexapole fields or for correction of astigmatism.

An exemplary embodiment of an arrangement including an aperture assemblyand a blanking device is shown in FIG. 2. A beam splitter, e.g. anaperture arrangement and deflector, can be provided by a first wafer201. An active part including e.g. electrostatic deflectors of the beamblanker can be provided by a wafer 203. The wafer 203 can be connected,for example, physically connected to the beam splitter by wafer 202. Forexample, one bore 222 per beamlet can be provided. According to someembodiments, which can be combined with other embodiments describedherein, a fourth wafer 204 may be provided. The fourth wafer 204 mayalso have a further bore 242 per beamlet. The 4 wafers can be accuratelypositioned and bonded together, e.g. with a lateral accuracy of <5microns per wafer. The bores 222 in wafer 202 and the bores 242 in wafer204 can include a conductive material or can consist of a conductivematerial. The wafers 202 and 204 can be grounded. The conductivematerial can act as a barrier for electrostatic cross talk between ablanked beam and neighboring beams.

According to some embodiments, which can be combined with otherembodiments described herein, a blanking device can be provided on afirst wafer and the shielding element, such as a second (further)shielding element can be provided on or by a second wafer. The secondshield element and/or a third shield element may have a first borediameter, and may further include one or more first apertures for abeamlet, e.g. a first beamlet, having a first aperture diameterdifferent from the first bore diameter.

According to some embodiments, wafer 202 and/or wafer 204 can have thesame length (wafer thickness) as the active blanking element, and may bemade from a silicon wafer. This may result in easier manufacturing.Additionally or alternatively, and as exemplarily shown for the fourthwafer 204, an aperture 244 can be provided. The aperture 244 isprovided, for example, additionally to the bore 242. FIG. 2 shows anaperture 244 at an upper side (one side) of the wafer 204. Apertures 244can be provided at a first side, a second side, or both sides. Theapertures are configured to further reduce crosstalk. According to someembodiments, which can be combined with other embodiments describedherein, the aperture may be at least 1.5 times larger than a beamdefining aperture of the wafer.

FIG. 2 shows the first wafer 201 having deflectors 211 and apertures214. The bores 222 in wafer 202 and the bores 242 in wafer 204 provideshield elements 245 of a shield assembly 155 to reduce crosstalk. Thewafer 203 includes blanking deflectors 231 to deflect the beam towardsbeam dump downstream of the blanking device. Further, shielding elements255 are provided.

It is beneficial to separate dynamic and static electric signals.Accordingly, the deflectors 211 of the beam splitter and the blankingdeflectors 231 of the blanking device can be provided according to someembodiments of the present disclosure. Voltages on the deflector 211 canbe constant and the blanking deflectors can be used to steer the beamletto the beam dump. For example, the blanker can have a strongerdeflection field as compared to the beam splitter. Having a strongerblanking deflector is beneficial, as the beam dump may be located farenough from the primary beamlets, for example, to avoid contaminationand/or charging of a region close to the beamlets. According to someembodiments, which can be combined with other embodiments describedherein, the blanker electrodes of the blanking deflector 231 can becloser together as compared to the electrodes of the deflector 211. Forexample, embodiments described herein may have an opening betweenelectrodes of the blanking deflector of 1 mm or below, such as 0.5 mm orbelow, particularly 0.25 mm or below. Additionally or alternatively, theblanking device may utilize larger voltages.

According to further embodiments, which can be combined with otherembodiments described herein, an arrangement of a beam splitter and ablanking device may deviate from the example explained with respect toFIG. 2. For example, the second wafer 202 may not be provided and thewafer 201 and the wafer 203 may be bonded directly to each other.Additionally or alternatively, wafers may be unattached (not bonded) andvacuum may be provided between adjacent wafers.

FIG. 3A shows an embodiment that may be combined with other embodimentsdescribed herein, wherein the blanking device 150 is upstream of thebeam splitter 330. Further beam limiting apertures 344 can be provided.The beam-limiting apertures may reduce or prevent stray electronsfalling on the blanking deflectors 231.

According to embodiments described herein, deflectors of a beam splitterand blanking deflectors can be provided per beamlet. For example, FIG.3A shows blanking deflectors 231. The blanking deflectors includeelectrodes creating a dipole field to steer the beamlets towards a beamstop or beam dump that can be provided downstream (see for example FIG.1A). Beam limiting apertures 344 are provided to reduce contaminationand/or charging of the blanking deflectors. A bore 242 at shieldingelements 255 is provided. The shielding elements 255 reduce crosstalkbetween the beamlets. According to some embodiments, which can becombined with other embodiments described herein, the blankingdeflectors are provided between the shielding elements and/or can besurrounded by the shielding elements. For example, the blankingdeflectors can be provided in a bore provided at the shielding elements.According to various embodiments, the beam splitter may separate thebeamlets in the plane of the specimen, e.g. while the emitter tip of thecharged particle source is imaged on the specimen. In other words,virtual sources may be generated in the plane of the charged particlesource. Yet further, according to various implementations, the beamsplitter can be provided by a plurality of multipole arrangement actingindividually on beamlets in the column, by a lens acting on thebeamlets, or by a combination of a lens an a multipole arrangement. Forexample, a lens may be arranged in a focus plane of the primary chargedparticle beamlets According to some embodiments, the lens may be anacceleration lens.

Another example of a blanking device can be described with respect toFIG. 3B. Deflectors 211 of a beam splitter and blanking deflectors 231can be provided surrounded by shielding elements 255. As describedabove, blanking deflectors and deflectors of a beam splitter may beelectrically isolated from each other and/or may provide differentphysical entities. Yet further, deflectors of a beam splitter can form aportion of the blanking device. For example, electrodes may be utilizedas part of a deflector of a beam splitter and as a part of blankingdeflectors 231. If crosstalk is generated by blanking, the crosstalk maybe represented by a multipole analysis. Typically, the largestcomponents will be a dipole or quadrupole (stigmation) crosstalk. Thismay be corrected if deflector electrodes as exemplarily shown in FIG. 3Bare provided as octupoles.

As shown in FIG. 3B, a blanking device may be a part of a beam splitter.The deflectors 211 can be operated for beam splitting or may beactivated together with the blanking deflectors 231 for blanking of thebeamlets, particularly for individual blanking of the beamlets.

As shown in FIG. 3C, a blanking device may be at the same position alongan optical axis (same z-position) as a beam splitter. The deflectors canbe operated for beam splitting or may be activated as blankingdeflectors 231 for blanking of the beamlets, particularly for individualblanking of the beamlets. Fields for blanking and splitting can besuperposed. Further, different deflectors having various positions inthe same plane at a z-position may be utilized. Some of the deflectorsmay act as blanking deflectors and some of the deflectors may act asbeam splitting deflectors. For example, a multipole device having shieldelements can be provided. According to yet further additional oralternative modifications, the multipole device can be controlled toadditionally generate aberration correction fields, e.g. for correctionof hexapole fields or for correction of astigmatism.

An arrangement of electrodes of a blanking deflector 231 isschematically shown in FIG. 4. FIG. 4 shows a view along an optical axisof a beamlet. The blanker electrode 412 may be connected to a controllerto be biased to opposite potentials. For example, the upper blankerelectrode 412 may have a voltage of about +100V and the lower blankerelectrode 412 may have a voltage of about −100 V. An antisymmetricvoltage distribution is provided. As compared to a blanking deflectorwith a single electrode, this may be beneficial since the antisymmetricarrangement produces less astigmatism in the blanked beam. The size forbeam dump or beam stop can, thus, be reduced. Further, a positive andnegative voltage reduces the overall voltage as compared to a singleelectrode having, for example, a reference to ground. Accordingly, asimilar deflection angle for beam blanking can be realized with reducedabsolute voltages reducing the risk of arcing and/or provides easiervacuum feedthroughs. The blanking deflector 231 may further includeadjustment electrodes 414. The adjustment electrodes may allow for beamadjustment during blanking or imaging. According to some embodiments,which can be combined with other embodiments described herein,insulators provided between the blanking deflector and/or the adjustmentdeflector or provided to support the blanking deflector and/or theadjustment deflector can be coated with a thin layer of carbon. Forexample, the thickness of the layer can be 100 nm or below and/or 5 nmor above, particularly 50 nm or below. The thin layer of carbon providesa high resistance layer and allows for reduction of charge build-up onthe insulators. According to some embodiments, which can be combinedwith other embodiments described herein, a blanking device includesinsulators having a carbon coating.

According to embodiments of the present disclosure, which can becombined with other embodiments described herein, the blanker electrode412 may form an arc of about 120°. For example, an arc may be of atleast 100° and/or at maximum 140°. A corresponding dipole field hasreduced or no hexapole component. This may further reduce the size ofthe beam profile for a blank beam and allows for reducing the size of abeam dump or beam stop.

Embodiments of the present disclosure include the shield assembly havingone or more of shielding elements surrounding blanking deflectors,shielding elements upstream and/or downstream of blanking deflectors,and shielding apertures, i.e. apertures with a reduced opening diameteras compared to bores in shielding elements. For example, a firstshielding element can at least partially surround a blanking deflectorof a first beamlet and the shield assembly may further include at leasta second shielding element, e.g. a second shielding element or a secondand a third shielding element, upstream (and/or downstream) of the firstblanking deflector.

According to yet further embodiments, which can be combined with otherembodiments described herein, a blanking device can have a length alongthe optical axis of 250 μm or above, for example 400 μm or above. Thelength of the blanking device having the shielding assembly furtherimproves the reduced crosstalk.

Accordingly, crosstalk can be reduced by at least one order of magnitudeas compared to known blankers and may be less than 0.1% or less thaneven 0.01%. Accordingly, blanking of one beamlet does not influence aneighboring beamlet. Further, the electrostatic deflectors shown hereinare fast. Both advantages are particularly useful for electron beaminspection systems, wherein imaging of a specimen or a sample with aplurality of beamlets within one column is provided.

FIG. 5A shows an electrostatic multipole device 500 that can be used inembodiments described herein. The electrostatic multipole device 500 maybe part of a blanking device 150 and can provide a blanking deflector231 for a beamlet. For example, the electrostatic multipole device 500can be provided as an octupole device. However, in some embodiments, themultipole device 500 may have less or more than eight electrodes.

The multipole device 500 includes a support device 505 which is at leastpartially coated with the high-resistance layer 510. In someembodiments, only a surface of the support device 505 which faces towardthe optical axis is coated with the high-resistance layer. In someembodiments, one or more side surfaces of the support device 505 whichmay extend perpendicularly to the optical axis are coated with ahigh-resistance material. In some embodiments, the entire outer surfaceof the support device 505 may be coated with a high-resistance material,so that an accumulation of surface charges on the multipole devicesurface may be reduced or entirely avoided.

According to yet further implementations, which may optionally beprovided for embodiments described herein, blanking deflectors may becoated with a thin layer of carbon, for example, having a thickness of10 μm or below, such as 100 nm or below, such as about 20 nm. A thinlayer of carbon has a high resistance allowing a voltage for blanking tobe maintained and further allowing undesired charges (accidentalcurrents from stray electrons) to drain away. For example, the outersurface of the support device may be entirely covered with a thin layerof a high-resistant material such as carbon, wherein the layer thicknesscan be in a range between 5 nm and 100 nm. Alternatively, thehigh-resistance layer can be 50 nm or below.

In some embodiments, which may be combined with other embodimentsdescribed herein, the support device 505 comprises a silicon waferand/or a base plate made of an insulating material. In some embodiments,the support device 505 is at least partially coated with an insulatingmaterial, which may at least partially be coated with thehigh-resistance layer. In particular, the high-resistance layer may becoated onto an insulating surface. Such an arrangement may guaranteethat a predetermined resistance between the individual electricalcontacts is provided via the high-resistance layer.

In the embodiment shown in FIG. 5A, the support device 505 comprises anopening for the charged particle beam, wherein at least a cylindricalinner surface of the opening is coated with the high-resistance layer510. Thus, the main surface 540 of the high-resistance layer 510 extendsparallel to the optical axis A and may entirely surround the opticalaxis A, without any gaps or discontinuities along the circumferentialdirection.

In some embodiments, which may be combined with other embodimentsdescribed herein, the cylindrical inner surface of the opening extendsover more than 0.2 mm and/or less than 5 mm, particularly over more than0.5 mm and/or less than 2 mm in the direction of the optical axis A. Inother words, the high-resistance layer 510 may extend parallel to theoptical axis over more than 0.2 mm and/or less than 5 mm. Thus, amultipole electric field which is essentially homogenous in thepropagation direction may act on the charged particle beam over adistance of more than 0.2 mm. The effect of fringe fields which may bepresent at the entrance and at the exit of the opening may be decreasedby providing a long propagation distance within the opening.

The electrostatic octupole device shown in FIG. 5A includes eightelectrical contacts, wherein each electrical contact contacts thehigh-resistance layer 510 at an associated circumferential position. Thecircumferential positions may be spaced apart at regular intervals of45°. At least one of the electrical contacts, e.g. the first electricalcontact 521 and/or the second electrical contact 522 may be provided asa conducting line which extends in a radial direction toward or on topof the high-conductive layer.

In some embodiments, the electrical contacts 521, 522 may be provided onat least one side surface of the support device 505, e.g. on the surfacedirected toward an entrance side (see FIG. 5B) of the opening and/or onthe surface directed toward an exit side 154 (see FIG. 5B) of theopening. The side surface may have been previously coated with thehigh-resistance material.

As can be seen in the sectional view of FIG. 5B, in some embodiments, atleast one electrical contact includes a first conductive line 551 whichradially extends at an entrance side (upstream side) of the cylindricalopening and a second conductive line 553 which radially extends at anexit side 154 (downstream side) of the cylindrical opening at acorresponding angular position. Both the first conductive line and thesecond conductive line may contact the high-resistance layer 510 at thefirst circumferential position 531. During operation, the firstconductive line and the second conductive line may be connected to thefirst electrical potential P1. By providing the first electrical contact521 with two conductive lines contacting the high-resistance layer atopposing sides of the opening, the main surface 540 of thehigh-resistance layer 510 may be held at an essentially constantpotential P1 at the first circumferential position 531 from the entranceside through to the exit side. A second electrical potential P2 can beprovided at a second circumferential position 532. As described above,according to some embodiments, the first potential P1 and the secondpotential P2 may be antisymmetric.

According to embodiments of the present disclosure, charge control canbe provided for multi-beam charged particle beam devices by blanking ofcharged particle beams individually. Individual blanking for multi-beamcharged particle beam devices increases the throughput, particularly forelectron beam inspection, i.e. inspection of a wafer.

Blanking of charged particle beamlets can be provided by blankingdevice, and particularly by blanking device in combination with beamdump. A beam dump can provide a trap for charged particle beamlets and,beneficially, captures electrons of the primary beamlet. Further,reducing escaping electrons of the primary beamlet as well as number ofescaping secondary electrons or backscattered electrons improves theperformance of the multi-beam charged particle beam device.

Examples of common beam dumps may include a Faraday cup. A Faraday cupmay be used to measure the current entering the Faraday cup. However, aFaraday cup may not be useful as a beam dump for multi-beam chargedparticle beam device.

A charged particle beam dump for a multi-beam charged particle beamdevice according to embodiments of the present disclosure includes anannular shaped body having an inner perimeter wall that defines an openannulus for trespassing of primary charged particle beamlets, theannular shaped body having an outer perimeter wall and a bottom wall.Further an annular shaped electrode provided partially above the annularshaped body is provided. The annular shaped electrode has an innerperimeter side and an outer perimeter side, wherein the inner perimeterside is outside of the radius of the inner perimeter wall of the annularshaped body.

A beam dump 160 shown in FIGS. 7A and 7B, includes an annular shapedbody. An inner perimeter wall 640 provides a center opening. Un-blankedbeamlets, for example, beamlet 14A, can pass through the center opening.According to some embodiments, which can be combined with otherembodiments described herein, an aperture plate with openings forindividual beamlets may be provided in the center opening. A blankedbeamlet, for example beamlet 14B, enters a ring-shaped opening. Thering-shaped opening can be provided between the inner perimeter wall 640of the annular body and an inner perimeter side of an annular shapedelectrode 610. The annular shaped electrode 610 can include the innerperimeter side and an outer perimeter side 612, opposing the innerperimeter side. The annular opening, i.e. the opening provided betweenthe diameters 642 and the diameter 618 can be small as compared to thelength of the beam dump 160, for example, the length along the opticalaxis. For example, the length of the beam dump 160 or of the annularbody, respectively, can be at least five times the width of the annularopening ((diameter 618−diameter 642) times 0.5).

According to embodiments of the present disclosure, the terms “annular”and/or “annulus” is not delimited to describe circular structures. Thegeometry may also be slightly oval or polygon-shape, e.g. hexagonal orsquare. An annular structure can be described as ring-shaped, wherein abody has an outer perimeter wall and an inner perimeter wall defining anopening in the structure. Typically, a rotational symmetric shape can bebeneficial. As such, a circular shape may be preferred as it providesthe highest order of rotational symmetry.

According to some embodiments, the annular body has the inner perimeterwall 640, an outer perimeter wall 620, and a bottom wall 630. The bottomwall may close the annular shaped body at a bottom side of the angularshape body. According to some embodiments, which can be combined withother embodiments described herein, the bottom wall has an inclinedsurface. The inclined surface can be inclined radially outwardly. Thebottom of the beam dump being inclined, i.e. specially angled, can serveto direct backscattered electrons or secondary electrons radial outwardsto prevent the backscattered electrons or secondary electrons fromescaping the beam dump.

As shown in FIGS. 7A and 7B, the outer perimeter side 612 of the annularshaped electrode 610 extends beyond the radius of the outer perimeterwall of the angular shape body. Alternatively, the outer perimeter sideof the annular shaped body may extend up to the radius of the outerperimeter wall of the angular shape body. The annular shaped electrodepartly closes the upper side of the angular shape body, for example, totrap charged particles in the beam dump.

According to some embodiments, which can be combined with otherembodiments described herein, an electrode 650 is provided within theangular shape body. The electrode can be annular shaped, i.e.cylindrical or ring-shaped. The electrode can be provided fully orpartially below the annular shaped electrode. As shown in FIG. 7B, theelectrode 650 is connected to a power supply 652. The power supply isconfigured to bias the electrode to a positive potential, for example,400 V or below, such as about 200 V. The electrode, such as the ringelectrode assists to collect electrons, such as secondary orbackscattered electrons, by generating an electric field that deflectselectrons. The electric field of the electrode 650 can be shielded tothe outside by the annular shaped electrode 610 and the walls of theangular shape body.

Since the blanked beam is confined in the angular shaped body and hashigh energy, it travels to the bottom of the annular shaped body withouthitting a side wall. At the bottom of the beam dump, for example, thebottom wall 630, which may have the inclined portion 632, the primarybeamlet interacts with the material and create secondary and/orbackscattered electrons often energy larger 0 eV and with angles of 0°to 90°. The long narrow geometry of the beam dump allows only electronswith low radial angles to escape. As described above, the inclinedportion 632 may increase radial angles. To reduce number of electronsescaping the beam dump, the electric field generated by the electrode650 is provided. The combination of geometry and the electrode 650allows for trapping electrons up to several kV.

According to some embodiments, which can be combined with otherembodiments described herein, at least the bottom wall 630 or, forexample, the bottom wall and the inner perimeter wall 640 can besupported by an insulating support. An insulating supports allows tomeasure the beam current of a beamlet impinging on the bottom wall orthe bottom wall and the inner perimeter wall 640, respectively.Measuring of the beam current can be particularly beneficial foraligning of the charged particle beam device. A beamlet can be deflectedinto the beam dump while the beamlet current is measured. The beamletcurrent can be evaluated to determine whether the beamlet impinges e.g.on the bottom wall. For example, the deflection angle of the beamlet canbe adjusted by verifying whether the beamlet impinges at the bottomwall. Accordingly, a method for operating a charged particle beam devicemay include generating a primary charged particle beam; generating afirst beamlet from the primary charged particle beam and a secondbeamlet from the primary charged particle beam; scanning the firstbeamlet and the second beamlet over a specimen; and guiding the firstbeamlet with a first deflection field of a first blanking deflector intoan annular shaped body of a charged particle beam dump. Further, themethod may include calibrating a deflection angle to guide the firstbeamlet in the beam dump by measuring a current of the first beamlet inthe beam dump.

According to embodiments of the present disclosure, the annular shape ofthe beam dump and/or the annular shaped of the opening at the upper sideof the beam dump enables easy deflection of different beamlets of themulti-beam charged particle beam device into the beam dump. Further, thering-shaped electrode in the annular shaped body facilitates collectingof electrons in the annular shaped body for multi-beam applications.According to some embodiments, which can be combined with otherembodiments described herein, the angular shape may be particularlybeneficial for aperture arrangements having openings provided on a ring,i.e. different beamlets providing on a ring.

According to some embodiments, which can be combined with otherembodiments described herein, the deep beam dump may be provideddownstream of the aperture arrangement and/or a beam splitter. Forexample, the beam dump can be provided at a position along the opticalaxis such that unplanned beamlets and blanked beamlets have a deflectionof only a few mrads (e.g. 10 mrads or below). Yet further, additionallyor alternatively the beam dump can be at the position of a common crossover of unplanned beamlets or a position, at which unplanned beamletsare close together.

According to yet further optional embodiments, an inner surface of theannular shaped body can be coated with a material reducing generation ofbackscattered or secondary particles. The yield of particles that mayescape the beam dump can be reduced.

Yet further, the beam dump as described herein may be combined withblanking device having a shield assembly as described herein. Accordingto some embodiments, the beam dump may also be provided for single-beamapplications having a single charged particle beam, for example a singlecharged particle beam scanned over a specimen, such as a SEM.

Some embodiments of the present disclosure including a blanking devicehaving a shielding assembly and/or a beam dump may refer to multi-beamapplications or multi-beamlet applications, wherein two or more chargedparticle beams, such as electrons beams, are guided in one column. Themultiple beams or beamlets can be scanned over a specimen. The specimencan be a wafer, e.g. during semiconductor manufacturing. Individualbeams or beamlets can be blanked. Applications can include one or moreapplications from the group: electron beam inspection (EBI), hot spot(HS) inspection, critical dimensioning (CD) applications, defect review(DR) applications, mask inspection, and lithography. Lithography mayhave no detection or less sophisticated detection of signal beamlets.Beam blanking for individual beamlets may, however, also be applied forsuch other applications, e.g. lithography. Yet further, applications ofmulti-beam charged particle beam devices may include biomedical andbiological applications

Embodiments of the present disclosure may further relate to method foroperating a charged particle beam device. The method includes generatinga primary charged particle beam; generating a first beamlet from theprimary charged particle beam and a second beamlet from the primarycharged particle beam; scanning the first beamlet and the second beamletover a specimen; guiding the first beamlet with a first deflection fieldof a first blanking deflector into an annular shaped body of a chargedparticle beam dump, particularly a charged particle beam dump accordingto embodiments of the present disclosure. Electrons can be attractedtowards the electrode 650 in the annular shaped body of the beam dump.Further, charged particle beam devices may be trapped according toaspects, details and modifications described herein.

High throughput electron beam inspection (EBI) systems can utilizemulti-beam charged particle beam devices, such as electron microscopes,that are able to create, focus and scan multiple primary chargedparticle beams or beamlets inside a single column of the chargedparticle beam device. A sample can be scanned by an array of focusedprimary charged particle beamlets, which in turn create multiple signalcharged particle beams or beamlets. The individual signal chargedparticle beamlets can be mapped onto one or more detection elements. Forexample, the signal charged particle beamlets can be detected on-axisor, as is illustrated in FIG. 1A, off-axis. According to embodimentsdescribed herein, a blanking device 150 (see FIG. 1A) having a shieldassembly 155 is provided. The shield assembly reduces crosstalk from ablanked beamlet to a neighboring beamlet. Further, a deflector ormultipole device (see for example FIGS. 4, 5A and 5B) can beelectrostatic and can be designed for fast blanking.

Blanking of beamlets, i.e. individual blanking of one or more beamletsof a plurality of beamlets can be provided according to embodiments ofmethods for operating a charged particle beam device as exemplarilyillustrated in FIG. 6. A primary charged particle beam is generated (seebox 602), for example, with a charged particle source 20 (see FIG. 1A).A plurality of beamlets are generated by an aperture arrangement 120.For example, as illustrated by box 604, a first beamlet is generatedfrom the primary charged particle beam and a second beamlet is generatedfrom the primary charged particle beam. The first beamlet and the secondbeamlet are scanned over a specimen (see box 606). For example, thefirst beamlet and the second beamlet can be scanned in a synchronizedmanner by a scanning deflector 12 shown in FIG. 1A. A beamlet isblanked, e.g. deflected in beam dump. As illustrated by box 608, thefirst beamlet may be deflected or blanked with a first deflection fieldof a first blanking deflector for the first beamlet. The firstdeflection field of the first blanking deflector is shielded (see box610) to reduce crosstalk to the second beamlet. Accordingly, one or moreof the beamlets scanning over the insulator can be blanked. Scanning ofthe other beams can be provided.

As described above, according to some implementations, the firstdeflection field is generated by antisymmetric potentials applied to thefirst blanking deflector.

While the foregoing is directed to embodiments of the disclosure, otherand further embodiments of the disclosure may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

The invention claimed is:
 1. A multi-beam charged particle beam device,comprising: a charged particle source configured to emit a primarycharged particle beam; an aperture arrangement having openingsconfigured to generate at least a first beamlet and a second beamlet ofthe primary charged particle beam; and a blanking device, the blankingdevice comprises: at least a first blanking deflector for the firstbeamlet and a second blanking deflector for the second beamlet; and ashield assembly having a first shielding element partially or fullysurrounding the first blanking deflector, the first blanking deflectorprovided in a bore of the first shielding element.
 2. The multi-beamcharged particle beam device according to claim 1, wherein the shieldassembly is configured to reduce cross-talk from the first blankingdeflector to the second beamlet.
 3. The multi-beam charged particle beamdevice according to claim 1, the shield assembly further comprises: asecond shielding element for the first beamlet upstream of the firstblanking deflector.
 4. The multi-beam charged particle beam deviceaccording to claim 3, wherein the blanking device is provided on a firstwafer and the second shielding element is provided on or by a secondwafer.
 5. The multi-beam charged particle beam device according to claim4, further comprising: a multipole arrangement configured to act on thefirst beamlet and the second beamlet separately, wherein the multipolearrangement is provided on a third wafer, and wherein the first wafer,the second wafer and the third wafer are stacked on top of each other inan arbitrary order.
 6. The multi-beam charged particle beam deviceaccording to claim 3, wherein the second shielding element has a firstbore diameter, and further comprises one or more first apertures for thefirst beamlet having a first aperture diameter different from the firstbore diameter.
 7. The multi-beam charged particle beam device accordingto claim 1, the shield assembly further comprises: a third shieldingelement for the first beamlet downstream of the first blankingdeflector.
 8. The multi-beam charged particle beam device according toclaim 7, wherein the third shielding element has a second bore diameter,and further comprises one or more second apertures for the first beamlethaving a second aperture diameter different from the second borediameter.
 9. The multi-charged particle beam device according to claim1, wherein the first blanking deflector includes a multipole device forsplitting the first beamlet from the second beamlet.
 10. Themulti-charged particle beam according to claim 9, wherein the splittingof the first beamlet and the second beamlet provides at least one ofseparate beamlet positions on a specimen or virtual sources of the firstbeamlet and the second beamlet in a plane perpendicular to an opticalaxis.
 11. The multi-beam charged particle beam device according to claim1, further comprising: a multipole arrangement configured to act on thefirst beamlet and the second beamlet separately.
 12. The multi-beamcharged particle beam device according to claim 11, wherein themultipole arrangement is provided on a third wafer.
 13. The multi-beamcharged particle beam device according to claim 11, wherein themultipole arrangement and the blanking device are provided on a firstwafer.
 14. The multi-beam charged particle beam device according toclaim 1, wherein the blanking device has a length along an optical axisof 250 μm or above.
 15. The multi-beam charged particle beam deviceaccording to claim 1, further comprising: a beam dump for the firstbeamlet and the second beamlet.
 16. The multi-beam charged particle beamdevice according to claim 1, further comprising: a detector assemblyhaving a first sensor to detect a first signal beamlet generated by thefirst beamlet and a second sensor to detect a second signal beamletgenerated by the second beamlet.
 17. The multi-beam charged particlebeam device according to claim 1, wherein the shield assembly furthercomprises a second shielding element for the first beamlet upstream ofthe first blanking deflector, and a third shielding element for thefirst beamlet downstream of the first blanking deflector.
 18. Themulti-beam charged particle beam device according to claim 1, whereinthe first shielding element fully surrounds the first blanking deflectorin a plane of the first blanking deflector.
 19. A multi-beam chargedparticle beam device, comprising: a charged particle source configuredto emit a primary charged particle beam; an aperture arrangement havingopenings configured to generate at least a first beamlet and a secondbeamlet of the primary charged particle beam; and a blanking device, theblanking device comprising: at least a first blanking deflector for thefirst beamlet and a second blanking deflector for the second beamlet;and a shield assembly having a first shielding element partially orfully surrounding the first blanking deflector wherein the firstblanking deflector includes an electrode having an arc of 100° or more.20. A multi-beam charged particle beam device, comprising: a chargedparticle source configured to emit a primary charged particle beam; anaperture arrangement having openings configured to generate at least afirst beamlet and a second beamlet of the primary charged particle beam;and a blanking device, the blanking device comprising: at least a firstblanking deflector for the first beamlet and a second blanking deflectorfor the second beamlet; and a shield assembly, including: a firstshielding element partially or fully surrounding the first blankingdeflector, a further first shielding element for the second beamlet andpartially or fully surrounding the second blanking deflector, a furthersecond shielding element for the second beamlet upstream of the furtherfirst blanking deflector, and a further third shielding element for thesecond beamlet downstream of the further first blanking deflector.
 21. Amethod for operating a charged particle beam device, comprising:generating a primary charged particle beam; generating a first beamletfrom the primary charged particle beam and a second beamlet from theprimary charged particle beam; scanning the first beamlet and the secondbeamlet over a specimen; blanking the first beamlet with a firstdeflection field of a first blanking deflector for the first beamlet;and shielding the first deflection field of the first blanking deflectorto reduce crosstalk to the second beamlet, the first blanking deflectorprovided in a bore of a first shielding element.
 22. The methodaccording to claim 21, wherein the first deflection field is generatedby antisymmetric potentials applied to the first blanking deflector.